From the equilateral (60-60-60) triangle with all legs of length 1, we can view half the triangle, forming a 30-60-90 triangle, with the hypotenuse measuring 1, the short leg1/2<span>, and the long leg 3 2. Therefore, we have sin 30° = </span>1/2<span>, cos 30° = 3 2, sin 60° = 3 2 and cos 60° = </span>1/2<span>.
i hope this help</span>
9x² + 7y² = 42
7y² = 42 - <span>9x²
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y² = (42 - <span>9x²)/7</span>
